This invention relates generally to fusible links and, more particularly, to an improved apparatus and method for forming fusible links on integrated circuits and like devices, such as silicon sensors.
Fusible links are employed extensively in integrated circuit technology. For example, memory elements such as integrated circuit programmable read only memories (PROMS) may be programmed by blowing various combinations of fusible links in the circuit in preselected patterns.
Fusible links for integrated circuits have been comprised of various materials and are generally formed by a narrowed or necked down section of a thin film conductor deposited upon a silicon substrate and insulated from the silicon substrate by a layer of silicon oxide. By applying a preselected voltage across the fusible link, a current is generated to stress the fuse until it fails. Fusible links have typically been constructed of combinations of silicon and chrome, nickel and chrome, molybdenum and silicon, and aluminum and silicon. The failure mechanism of such fusible links typically involves electromigration of the metallization. However, experience with fusible links has shown that voltage requirements to blow the fuses may vary significantly, compromising the reliability and reproducibility of devices based upon fusible links.